Abstract: in orderto reveal the compositon- bfurcation-composition formaton mechanism and coal accurulaton law of No. 2 seam group in South Zhongi survey Block with the sedimenolgy theory as the guidance,the cal and rock comparison and te ltofacies and palecgeography restoration metnod were applied to the study on the spatald str utin and the coalacumulatin law of N0o. 2 seam group.The resuts shcwed that No.2seam compostton at the west part and east part of the study block was named as No.2*seam and the bifurcation at the midele mnidle east par ofthe study block would have two local mineable seams as Nvo. 2 'seam and N0.2*covseam. T he sedimentary period litnfces and paleogeograplhy ditriution in No. 2 sean group showed that thecomostion block in the west part and east part ofthe seam w s mainly lcated in the delaplain facies zone the bfucatio t the midle and midle east partof the sean was mainly located at the delta leading edge and the shore lake facies and the thickness of the sean was thick.The composition-ificationcompostion features were controld by the balance between the accommodation space growh rate and the peat accurulation rate in the seam sedimentary percd. with the analysis on the coal acurulaton lav and the surounding coal exploration and developmen statos the paer hed that No. 2-seam at the west side of the study area would have a high resource potential and would be the potential target area of the late expanded survey work.